| Ratcheting Behavior refers to the cycle accumulation of plastic deformation under asymmetrical stress controlled cyclic loading,which may lead to reduced fatigue life or do not make the structure work normally. Studying on the ratcheting behavior of engineering materials and its constitutive model plays an important role in engineering application. In the last decades, the constitutive model describing ratcheting effect had also been greatly developed. But the available constitutive models are not so perfect and the predictions of ratcheting strain are not accurate enough. Therefore it is necessary to compare and evaluate the prediction capability of the available constitutive modelsBased on the experimental results of 316L stainless steel, aluminum, copper and U71Mn rail steel, this paper conducts the following work:(1) Six kinds of typical cyclic elastic-plastic constitutive models, including the Dafalias-Popov model, AF model, OW Ⅰ model, OW Ⅱ model, AF-OW Ⅰ model and AF-OW Ⅱ model were used to predict the cyclic deformation and uniaxial ratcheting behavior of 316L stainless steel, aluminum, copper and U71Mn rail steel. The results show that the predictive ability of AF-OW Ⅱ elastic- plastic model is superior to other elastic-plastic models.(2) Five kinds of tipical cyclic viscoplastic constitutive models, including the Dafalias-Popov model, AF model, OW Ⅰ model, OW Ⅱ model, AF-OW Ⅰ model and AF-OW Ⅱ model were used to predict the cyclic deformation and uniaxial ratcheting behavior of 316L stainless steel, aluminum, copper and U71Mn rail steel, pointing out the shortcomings of different models. The results also show that the predictive ability of AF-OW Ⅱ viscoplastic model is superior to other viscoplastic models.(3) Based on the evaluation of the cyclic constitutive models, an improvement is performed on the AF-OW Ⅰ model, and the revised model is verified by comparing its predictions with the experimental results. |
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